1. Field of the Invention
The invention relates to a device for the transmission of data and/or energy via conductors, at least one conductor thereof being subdivided into a first and a second conductor segment by at least one disconnecting unit, each disconnecting unit including at least one monitoring unit.
2. Description of the Related Art
When short-circuits occur between the two conductors or in the connected stations in a system in which data and/or energy is transmitted to a plurality of stations via two conductors, neither data nor energy can be transmitted and the feeding source is loaded to an inadmissible extent.
EP 0 626 743 A2 discloses a system in which disconnecting switches are controlled by means of different short-circuit switches in a two-conductor ring system. When a short-circuit occurs, the relevant conductor is disconnected by disconnecting switches in monitoring units. The remainder of the system, situated beyond the short-circuit, is fed with a voltage via switches in the beginning and end monitoring units from the other side where the two conductors enter the beginning and end monitoring unit again. Because at least one user must be connected between two monitoring units, in the case of a short-circuit at least this user, and possibly also several other users arranged between the monitoring units, will be switched off. The conductors, however, are tested for short-circuits only during switching on. Moreover, this system is designed only for DC voltages.
WO-A-92/10018 describes the sampling of conductors by means of current and voltage sensors and a controller evaluates the values determined and interrupts the conductors by means of semiconductor switches when a threshold voltage is exceeded. If these conductors are not interrupted in the case of failure of the switches, the controller opens a main fuse. This system serves not only to relieve the driving source, but notably to avoid arcing in the case of mechanically switched fuses.